THE GENE FOR AUTOSOMAL-DOMINANT HIDROTIC ECTODERMAL DYSPLASIA (CLOUSTON-SYNDROME) IN A LARGE INDIAN FAMILY MAPS TO THE 13Q11-Q12.1 PERICENTROMERIC REGION

Hidrotic ectodermal dysplasia (HED), Clouston syndrome (MIM No. 129500 ), is an autosomal dominant disorder affecting the skin and its deriva tives. It is characterized by alopecia, dysplastic nails in hands and feet, and hyperkeratosis of the palms and soles. We have studied a lar ge Indian pedigree (UR005), from Gujarat region, consisting of a total 127 individuals including 41 affected (12 males and 29 females). The phenotype in this family ranged from atrichosis to hypotrichosis, spar sity or absence of eyebrows, and thickening of palms and soles. In ord er to map the disease locus by linkage analysis, DNA polymorphisms wer e used in DNAs from 23 affected and 8 normal individuals. While genoty ping was in progress, Kibar et al. [1996] reported mapping of the locu s of a similar disease in French-Canadian families to 13q around marke r D13S141. We then utilized markers on 13q to genotype the members of the Indian family. Linkage with 13q11-12.1 markers was confirmed with a maximum lod score of 3.27 (theta=0.00) with locus D13S1316. Multipoi nt linkage analysis yielded a lod score of 5.04 at theta=0.00 with D13 S1316; haplotype analysis indicated that the gene for the Clouston syn drome in this family is localized proximal to D13S292. These data sugg est that the gene for the Clouston syndrome in this Indian pedigree is probably the same as that described in the French Canadian families. The combination of data from all available families linked to 13q11-12 .1 will make it possible to narrow the critical region and facilitate the positional cloning of the elusive gene. (C) 1997 Wiley-Liss, Inc.